// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/wm/core/window_modality_controller.h"

#include <stddef.h>

#include <algorithm>

#include "ui/aura/client/aura_constants.h"
#include "ui/aura/client/capture_client.h"
#include "ui/aura/env.h"
#include "ui/aura/window.h"
#include "ui/aura/window_event_dispatcher.h"
#include "ui/aura/window_property.h"
#include "ui/base/ui_base_types.h"
#include "ui/events/event.h"
#include "ui/events/event_target.h"
#include "ui/events/gestures/gesture_recognizer.h"
#include "ui/wm/core/window_animations.h"
#include "ui/wm/core/window_util.h"

namespace wm {

// Transient child's modal parent.
extern const aura::WindowProperty<aura::Window*>* const kModalParentKey;
DEFINE_WINDOW_PROPERTY_KEY(aura::Window*, kModalParentKey, NULL);

namespace {

    bool HasAncestor(aura::Window* window, aura::Window* ancestor)
    {
        if (!window)
            return false;
        if (window == ancestor)
            return true;
        return HasAncestor(window->parent(), ancestor);
    }

    bool TransientChildIsWindowModal(aura::Window* window)
    {
        return window->GetProperty(aura::client::kModalKey) == ui::MODAL_TYPE_WINDOW;
    }

    bool TransientChildIsSystemModal(aura::Window* window)
    {
        return window->GetProperty(aura::client::kModalKey) == ui::MODAL_TYPE_SYSTEM;
    }

    bool TransientChildIsChildModal(aura::Window* window)
    {
        return window->GetProperty(aura::client::kModalKey) == ui::MODAL_TYPE_CHILD;
    }

    aura::Window* GetModalParent(aura::Window* window)
    {
        return window->GetProperty(kModalParentKey);
    }

    bool IsModalTransientChild(aura::Window* transient, aura::Window* original)
    {
        return transient->IsVisible() && (TransientChildIsWindowModal(transient) || TransientChildIsSystemModal(transient) || (TransientChildIsChildModal(transient) && (HasAncestor(original, GetModalParent(transient)))));
    }

    aura::Window* GetModalTransientChild(
        aura::Window* activatable,
        aura::Window* original)
    {
        for (aura::Window::Windows::const_iterator it = GetTransientChildren(activatable).begin();
             it != GetTransientChildren(activatable).end();
             ++it) {
            aura::Window* transient = *it;
            if (IsModalTransientChild(transient, original)) {
                if (GetTransientChildren(transient).empty())
                    return transient;

                aura::Window* modal_child = GetModalTransientChild(transient, original);
                return modal_child ? modal_child : transient;
            }
        }
        return NULL;
    }

} // namespace

void SetModalParent(aura::Window* child, aura::Window* parent)
{
    child->SetProperty(kModalParentKey, parent);
}

aura::Window* GetModalTransient(aura::Window* window)
{
    if (!window)
        return NULL;

    // We always want to check the for the transient child of the toplevel window.
    aura::Window* toplevel = GetToplevelWindow(window);
    if (!toplevel)
        return NULL;

    return GetModalTransientChild(toplevel, window);
}

////////////////////////////////////////////////////////////////////////////////
// WindowModalityController, public:

WindowModalityController::WindowModalityController(
    ui::EventTarget* event_target)
    : event_target_(event_target)
{
    aura::Env::GetInstance()->AddObserver(this);
    DCHECK(event_target->IsPreTargetListEmpty());
    event_target_->AddPreTargetHandler(this);
}

WindowModalityController::~WindowModalityController()
{
    event_target_->RemovePreTargetHandler(this);
    aura::Env::GetInstance()->RemoveObserver(this);
    for (size_t i = 0; i < windows_.size(); ++i)
        windows_[i]->RemoveObserver(this);
}

////////////////////////////////////////////////////////////////////////////////
// WindowModalityController, aura::EventFilter implementation:

void WindowModalityController::OnKeyEvent(ui::KeyEvent* event)
{
    aura::Window* target = static_cast<aura::Window*>(event->target());
    if (GetModalTransient(target))
        event->SetHandled();
}

void WindowModalityController::OnMouseEvent(ui::MouseEvent* event)
{
    aura::Window* target = static_cast<aura::Window*>(event->target());
    if (ProcessLocatedEvent(target, event))
        event->SetHandled();
}

void WindowModalityController::OnTouchEvent(ui::TouchEvent* event)
{
    aura::Window* target = static_cast<aura::Window*>(event->target());
    if (ProcessLocatedEvent(target, event))
        event->SetHandled();
}

////////////////////////////////////////////////////////////////////////////////
// WindowModalityController, aura::EnvObserver implementation:

void WindowModalityController::OnWindowInitialized(aura::Window* window)
{
    windows_.push_back(window);
    window->AddObserver(this);
}

////////////////////////////////////////////////////////////////////////////////
// WindowModalityController, aura::WindowObserver implementation:

void WindowModalityController::OnWindowPropertyChanged(aura::Window* window,
    const void* key,
    intptr_t old)
{
    // In tests, we sometimes create the modality relationship after a window is
    // visible.
    if (key == aura::client::kModalKey && window->GetProperty(aura::client::kModalKey) != ui::MODAL_TYPE_NONE && window->IsVisible()) {
        ActivateWindow(window);
        ui::GestureRecognizer::Get()->CancelActiveTouchesExcept(nullptr);
    }
}

void WindowModalityController::OnWindowVisibilityChanged(
    aura::Window* window,
    bool visible)
{
    if (visible && window->GetProperty(aura::client::kModalKey) != ui::MODAL_TYPE_NONE) {
        ui::GestureRecognizer::Get()->CancelActiveTouchesExcept(nullptr);
        // Make sure no other window has capture, otherwise |window| won't get mouse
        // events.
        aura::Window* capture_window = aura::client::GetCaptureWindow(window);
        if (capture_window) {
            bool should_release_capture = true;
            if (window->GetProperty(aura::client::kModalKey) == ui::MODAL_TYPE_CHILD && !HasAncestor(capture_window, GetModalParent(window))) {
                // For child modal windows we only need ensure capture is not on a
                // descendant of the modal parent. This way we block events to the
                // parents subtree appropriately.
                should_release_capture = false;
            }

            if (should_release_capture)
                capture_window->ReleaseCapture();
        }
    }
}

void WindowModalityController::OnWindowDestroyed(aura::Window* window)
{
    windows_.erase(std::find(windows_.begin(), windows_.end(), window));
    window->RemoveObserver(this);
}

bool WindowModalityController::ProcessLocatedEvent(aura::Window* target,
    ui::LocatedEvent* event)
{
    if (event->handled())
        return false;
    aura::Window* modal_transient_child = GetModalTransient(target);
    if (modal_transient_child && (event->type() == ui::ET_MOUSE_PRESSED || event->type() == ui::ET_TOUCH_PRESSED)) {
        // Activate top window if transient child window is window modal.
        if (TransientChildIsWindowModal(modal_transient_child)) {
            aura::Window* toplevel = GetToplevelWindow(target);
            DCHECK(toplevel);
            ActivateWindow(toplevel);
        }

        AnimateWindow(modal_transient_child, WINDOW_ANIMATION_TYPE_BOUNCE);
    }
    if (event->type() == ui::ET_TOUCH_CANCELLED)
        return false;
    return !!modal_transient_child;
}

} // namespace wm
